000 WTPZ41 KNHC 162033 TCDEP1 TROPICAL STORM ESTELLE DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP062016 300 PM MDT SAT JUL 16 2016 Estelle's satellite presentation has changed very little since this morning, with a large convective band still wrapping around the western and southwestern portion of the circulation. Satellite data show that there is some northerly shear affecting Estelle, causing a north-south tilt between the low- and mid-level centers and a lack of convection over the northern part of the storm. Dvorak intensity estimates are unchanged since this morning and the initial intensity remains 45 kt, which is in agreement with a recent CIMSS AMSU intensity estimate. The northerly shear is forecast to relax during the next day or so, which should allow for strengthening while the tropical cyclone remains over warm water during the next few days. Estelle is expected to become a hurricane in about 24 hours, and reach peak intensity in 2 to 3 days. The NHC intensity forecast is again a little above the SHIPS/LGEM guidance, but in close agreement with the Florida State Super Ensemble (FSSE). The low-level center has been difficult to pinpoint today as several low cloud swirls have been rotating around a mean center. Based on the recent fixes of the mean center, the initial motion estimate is 290/7 kt. The tropical cyclone should continue on a west-northwestward heading during the next few days to the south of a subtropical ridge that extends westward from northern Mexico. The GFS continues to show less ridging than the ECMWF and has a track that is along the northern edge of the guidance envelope. Meanwhile, the ECMWF depicts a stronger ridge and a track more westward. The NHC track lies between these solutions and is again close to the FSSE. FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 15.8N 109.7W 45 KT 50 MPH 12H 17/0600Z 16.2N 110.8W 55 KT 65 MPH 24H 17/1800Z 16.7N 112.2W 65 KT 75 MPH 36H 18/0600Z 17.2N 113.7W 70 KT 80 MPH 48H 18/1800Z 17.7N 115.3W 75 KT 85 MPH 72H 19/1800Z 18.4N 118.9W 85 KT 100 MPH 96H 20/1800Z 18.9N 123.2W 80 KT 90 MPH 120H 21/1800Z 20.3N 128.3W 60 KT 70 MPH $$ Forecaster Brown